The present invention is related to converters, and more specifically to automatic disconnect of an alternating current (AC) source from a converter.
Due to cost and demand, efforts are constantly being made to conserve on the use of energy. This applies even to electricity used when a charging device is still connected to an AC source but the device being charged has been disconnected or is fully charged. Although a device may be disconnected from the charging device or fully charged, due to electronics today, the charging device may still be drawing power and burning energy. A charging device, such as a wall wart, receives AC power and includes a DC charging power supply with a DC converter and an isolation device between the AC source and the DC charging power supply where the DC charging power supply rectifies and steps down the AC power source to produce a suitable DC charging source usable for charging a rechargeable battery on a device. For example, existing phone chargers used to charge cell phones may use a transformer or switching converter that remains powered by the AC supply even when the phone is fully charged and no longer drawing a direct current (DC) charging current. This causes an energy consumption that adds to increased energy costs. This cost is further increased if one or more other devices are drawing unnecessary power. In many cases, a person is unaware of this unnecessary energy use.